Characterization of early maturing elite genotypes based on MTSI and MGIDI indexes:an illustration in upland cotton(Gossypium hirsutum L.)

Background Globally,the cultivation of cotton is constrained by its tendency for extended periods of growth.Early maturity plays a potential role in rainfed-based multiple cropping system especially in the current era of climate change.In the current study,a set of 20 diverse Gossypium hirsutum genotypes were evaluated in two crop seasons with three planting densities and assessed for 11 morphological traits related to early maturity.The study aimed to identify genotype(s)that mature rapidly and accomplish well under diverse environmental conditions based on the two robust multivariate techniques called multi-trait stability index(MTSI)and multi-trait genotype-ideotype distance index(MGIDI).Results MTSI analysis revealed that out of the 20 genotypes,three genotypes,viz.,NNDC-30,A-2,and S-32 accomplished well in terms of early maturity traits in two seasons.Furthermore,three genotypes were selected using MGIDI method for each planting densities with a selection intensity of 15%.The strengths and weaknesses of the genotypes selected based on MGIDI method highlighted that the breeders could focus on developing early-maturing genotypes with specific traits such as days to first flower and boll opening.The selected genotypes exhibited positive genetic gains for traits related to earliness and a successful harvest during the first and second pickings.However,there were negative gains for traits related to flowering and boll opening.Conclusion The study identified three genotypes exhibiting early maturity and accomplished well under different planting densities.The multivariate methods(MTSI and MGIDI)serve as novel approaches for selecting desired genotypes in plant breeding programs,especially across various growing environments.These methods offer exclusive benefits and can easily construe and minimize multicollinearity issues.

Cotton maturity and responses to harvest aids following chemical topping with mepiquat chloride during bloom period

Early maturity, complete defoliation and boll opening are essential for the efficient machine harvesting of cotton. Chemical topping, involving one extra application of mepiquat chloride(MC) in addition to its traditional multipleapplication strategy, may be able to replace manual topping. However, it is not known whether this chemical topping technique will influence maturity or cotton responses to harvest aids. In this 2-yr field study, we determined the effects of the timing of chemical topping using various rates of MC on boll opening percentage(BOP) before application of harvest aids(50% thidiazuron··ethephon suspension concentrate, referred to as TE), and the defoliation percentage(DP) and BOP 14 days after TE application. The results indicated that late chemical topping(near the physiological cutout, when the nodes above white flower is equal to 5.0) significantly decreased BOP before TE by 5.9–11.2% compared with early(at peak bloom) or middle(seven days after peak bloom) treatments in 2019, which was a relatively normal year based on crop condition. Also, a high MC rate(270 g ha) showed a significantly lower(22.0%) BOP before TE than low(90 g ha) or medium(180 g ha) rates. In 2020, which was characterized by stronger vegetative growth in the late season, the late chemical topping reduced the number of leaves before TE application relative to early or middle treatments, but had lower DP(23.2–27.2%) 14 days after TE application. The high MC rate showed a leaf count before TE application that was similar to the low and medium rates, but it showed the most leaves after TE and much lower(15.0–21.7%) DP in 2020. These results suggest that late timing of chemical topping and a high MC rate decreased the sensitivity of leaves to harvest aids. Further analysis indicated that the late chemical topping mainly affected the leaf drop from the mainstem and fruiting branches where the late regrowth occurred, and the high MC rate reduced leaf shedding from these parts and also from the vegetative branches. In conclusion, chemical topping with MC during the bloom period affected cotton maturity and responses to harvest aids in different ways according to the crop condition. To avoid the risks of delayed maturity and poor defoliation after the application of harvest aids, chemical topping should not be performed too late(i.e., near the physiological cutout) by using MC at more than 180 g ha. The optimum timing of chemical topping probably varies from peak bloom to around seven days later, and the safest MC rates for chemical topping should be less than 180 g ha.

Feasibility assessment of phenotyping cotton fiber maturity using infrared spectroscopy and algorithms for genotyping analyses

Background:Cotton fiber maturity is an important property that partially determines the processing and performance of cotton.Due to difficulties of obtaining fiber maturity values accurately from every plant of a genetic population,cotton geneticists often use micronaire(MIC) and/or lint percentage for classifying immature phenotypes from mature fiber phenotyp es although they are complex fiber traits.The recent development of an algorithm for determining cotton fiber maturity(MIR)from Fourier transform infrared(FT-IR)spectra explores a novel way to measure fiber maturity efficiently and accurately.However,the algorithm has not been tested with a genetic population consisting of a large number of progeny pla,nts.Results:The merits and limits of the MIC-or lint percentage-bas ed phenotyping method were demonstrated by comparing the observed phenotypes with the predicted phenotypes based on their DNA marker genotypes in a genetic population consisting of 708 F2 plants with various fiber maturity.The observed MIC-based fiber phenotypes matched to the predicted phenotypes better than the observed lint percenta ge-based fiber phenotypes.The lint percentage was obtained from each of F2 plants,whereas the MIC values were unable to be obtained from the entire population since certain F2 plants produced insufficient fiber mass for their measurements.To test the feasibiility of cotton fiber infrared maturity(MIR)as a viable phenotyping tool for genetic analyses,we me asured FT-IR spectra from the second population composed of 80 F2 plants with various fiber maturities,determined MIR values using the algorithms,and compared them with their genotypes in addition to other fiber phenotypes.The results showed that MIR values were successfully obtained from each of the F2 plants,and the observed MIR-based phenotypes fit well to the predicted phenotypes based on their DNA marker genotypes as well as the observed phenotypes based on a combination of MIC and lint percentage.Conclusions:The M,R value obtained from FT-IR spectra of cotton fibers is able to accurately assess fiber maturity of all plants of a population in a quantitative way.The technique provides an option for cotton geneticists to determine fiber maturity rapidly and efficiently.

Application of the cultural techniques of cotton leaf-age adjusting-controlling for promotng early maturity

According to the production index of lint cotton yield over 100kg per mu(1/15ha)and the relationship between the climate factors and the distribution of time and space for cottonboll setting in 1985—1990,we established a model of cultural techniques of cotton leaf-age-ad-justing-controlling for enhancing early maturity.By utilizing the principle of leaf-age model andthe principle of regulating nutrient distribution with DPC(Mepiquate chloride),the plants weretreated with DPC in proper time.A new type of population plant patterns was set up.It character-ized by high population density,dwarf,high boll weight,bolls near nodes,high energy and lowconsumption,short distance transport of nutrients,high yield and good quality.We put forward aset of management measures,i.e.adjusting boll setting stage,adjusting and controlling boll set-ting structure,stably applying N,increasing P,supplementing plants with K,increasing irrigationefficiency,techniques were applied and demonstrated in large areas in high yield

Feasibility study of assessing cotton fiber maturity from near infrared hyperspectral imaging technique

Background Fiber maturity is a key cotton quality property,and its variability in a sample impacts fiber processing and dyeing performance.Currently,the maturity is determined by using established protocols in laboratories under a controlled environment.There is an increasing need to measure fiber maturity using low-cost(in general less than $20000)and small portable systems.In this study,a laboratory feasibility was performed to assess the ability of the shortwave infrared hyperspectral imaging(SWIR HSI)technique for determining the conditioned fiber maturity,and as a comparison,a bench-top commercial and expensive(in general greater than $60000)near infrared(NIR)instrument was used.Results Although SWIR HSI and NIR represent different measurement technologies,consistent spectral characteristics were observed between the two instruments when they were used to measure the maturity of the locule fiber samples in seed cotton and of the well-defined fiber samples,respectively.Partial least squares(PLS)models were established using different spectral preprocessing parameters to predict fiber maturity.The high prediction precision was observed by a lower root mean square error of prediction(RMSEP)(<0.046),higher R_(p)^(2)(>0.518),and greater percentage(97.0%)of samples within the 95% agreement range in the entire NIR region(1000-2500 nm)without the moisture band at 1940 nm.Conclusion SWIR HSI has a good potential for assessing cotton fiber maturity in a laboratory environment.

Biochemical Genetic Mechanism and QTLs of Early Maturing without Yield Loss in Short-season Upland Cotton(Gossypium hirsutum L.)

The short season cotton(SSC) was important Upland plant ecotype(Gossypium hirsutum L.).The growth of SSC was very short that is 105 ～ 110 days(after planting). SSC could increase

Induction of Aneuploids and Their Identification in Upland Cotton

Aneuploid lines have been playing an importantrole in crop genetic studies and breedingutilization.Unfortunately,only several geneticmaterials of aneuploid can be used in Uplandcotton. So far,there are 16 monosomicsidentified in cotton.In order to fill the gap,wecarried on the irradiation research of

Reproductive Performance and Fiber Quality Responses of Cotton to Potassium Nutrition

Potassium (K) deficiency affects cotton growth and development and fiber properties. An experiment was conducted in an outdoor pot culture facility by imposing four potassium stress treatments (100%, 40%, 20% and 0% of optimum K level) prior to flowering during 2010 and 2011 growing season. Upland cotton cultivar, TM-1, was seeded in the pots comprised of fine sand as rooting medium. Flowers and bolls were tagged daily to estimate boll maturation period (BMP). Leaf samples were collected every four days from flowering to maturity to estimate leaf K content. Plant height and node numbers were recorded from emergence to 21 days after treatment. Photosynthesis and stomatal conductance were measured weekly from day of treatment imposition to physiological maturity at an interval of seven days. Stem, leaf, and boll dry-component weights, and boll numbers were recorded at the end of the experiment in each year. From each boll, the lint samples were collected and grouped based on average leaf potassium concentration during BMP, and fiber quality parameters were recorded for each group in each treatment. At high K deficient (0 K) condition, total biomass declined by 27% and 28% in years 2010 and 2011, respectively. Significantly, lower numbers of bolls were retained per plant at 0 K stress treatment during both the years. Leaf photosynthesis (r2 = 0.92) and stomatal conductance (r2 = 0.80) declined with declining leaf K levels. Fiber length, strength, micronaire, and uniformity declined linearly with decrease in leaf K content. Weaker fibers with medium length were produced under K-deficient conditions with micronaire values in the discount range. Fiber uniformity, however, did not decline with decrease in leaf K. The identified leaf K status-specific relationships for fiber properties could be used to improve management practices under potassium deficiency and to develop new sub-routines of the existing cotton simulation models. New and improved models will be useful not only in management, but also in arena of policy decisions including future climate change impact assessment analysis.

Solid State NMR Applied to Evaluate Fibers Cotton

The evaluation of cotton fibers from Nuclear Magnetic Resonance (NMR) in solid state using high and low-field showed to be a good alternative to evaluate these materials. The main objective of this work was to use the solid-state NMR techniques to accompany the fibers nature, size and morphology to have a direct method to evaluate cotton fibers maturity. We could conclude that the solid-state NMR techniques are good source to evaluate the molecular behavior of cotton short and long fibers and give important information on sample’s morphology, indicating that this technique can be used to distinguish the size of cotton fibers.

早熟优质宜机采棉花新品种‘徐棉608’的选育

针对粮棉争地、棉花生产用工多及劳动力成本逐渐增加等问题,以‘鲁棉19号’为母本‘、徐棉266’为父本,采用杂交育种技术育成早熟棉花新品种‘徐棉608’,该品种可以满足麦(蒜、油)后棉一年两熟种植制度且适宜机械化采收。在2018—2019年江苏省棉花新品种区域试验中,‘徐棉608’生育期99 d,衣分为40.1%,皮棉产量为1221.0 kg/hm^(2),较对照‘中棉所50’增产3.9%。株高87.5 cm,第一果枝节位高度20.8 cm,符合机采棉株型标准。纤维上半部平均长度为28.1 mm,断裂比强度为29.2 cN/tex,马克隆值为5.1。在2020年江苏省生产试验中,平均皮棉产量为1340.3 kg/hm^(2),较对照‘中棉所50’增产幅度高达10.5%。该品种衣分高,耐枯萎病和黄萎病,抗棉铃虫,耐盐性强,对脱叶催熟剂较敏感,适宜在江苏省及长江流域、黄河流域早熟棉区推广种植。

基于传感控制的自动采棉机系统设计

为了实现棉花依据成熟度进行采摘,基于图像传感器设计图像处理方法,完成棉桃图像特征提取,进而实现棉花成熟度评估和空间棉桃定位。采用HSV方案进行图像灰度处理,采用二维大津法进行图像分割,提取棉桃特征参数。对成熟棉花和未成熟棉花图像样本分析发现,棉桃图像轮廓周长L和面积S比大于0.31时棉花成熟,从而建立棉花采摘标准,并采用双目图像系统,实现目标棉桃的图像坐标向空间坐标的转换。对图像分割精度,棉桃提取精度和视觉定位精度进行测试,结果表明:系统具有较高的可靠性。

长绒棉棉铃成熟度仿生类脑分类方法研究

快速准确识别长绒棉棉铃成熟的不同阶段,对长绒棉种植的智能化、装备化管理具有重要意义。针对现有方法在长绒棉棉铃成熟度分类辨识易受复杂棉田背景、阴影、强光和叶片遮挡等因素影响识别率低的问题,提出将模拟生物视觉皮层的信息处理机制与HMAX模型融合的类脑分类方法,实现大田环境下棉铃不同成熟度的快速、高效识别。首先,采用相机获取长绒棉不同成熟阶段的图像信息,以花铃期、裂铃期、吐絮期、停止生长期4个生长阶段为对象,构建中小样本的棉铃数据集;其次,模拟视网膜神经节细胞的信息处理机制以提升HMAX模型的检测速度与精度,提出基于改进HMAX模型的类脑识别算法;最后,为探究各模型在非清晰数据集上的表现,采用高斯模糊方法将测试集转换6次,以HMAX、HHMAX、SHMAX作为对比,评估改进HMAX模型性能。试验结果表明,在原始数据集下,改进HMAX模型的总体准确率为95.3%,相比于HMAX、HHMAX、SHMAX模型分别高出15.1、9.2和6个百分点;在错误分类中,由于吐絮期和停止生长期特征相似,造成错误识别的概率最大;在非清晰数据集下,HMAX、HHMAX以及SHMAX退化指数分别为8.21%、7.935%和11.21%,改进HMAX模型总体退化指数为5.92%。研究结果表明:在分类精度、模糊图像输入等方面,改进HMAX模型能够较好地满足实际生产中棉铃不同成熟阶段分类识别的实际需求。

适宜早熟棉—荷兰豆套作的荷兰豆品种筛选试验

为稳定豫东地区棉花种植面积,提高复种指数,降低种植成本,提高农民经济收益,引进5个荷兰豆品种,以筛选出适宜在豫东地区和早熟棉套作的荷兰豆品种。结果显示,口感脆嫩、产量高的金船白花双荚818和豌豆6号,开花时间比较集中,便于采摘,株高和棉株相近,适宜攀附在早熟棉植株上进行套作;早熟棉套种金船白花双荚818综合经济效益为50223元/hm^(2),套种豌豆6号综合经济效益为49 319元/hm^(2),效益可观,值得在豫东地区大力推广。

缩节胺运筹对夏直播棉熟相的影响

为明确缩节胺运筹对夏直播棉熟相形成的影响,2018-2019年于扬州大学实验农场以中棉425为材料,设缩节胺用量0、180、360 g·hm^(-2)3个水平,施用时期分别设盛蕾期+初花期(施用比例1∶2)、盛蕾+初花期+盛花期(施用比例1∶2∶3) 2个运筹方式,同时设常规施用方式(初花期,缩节胺120 g·hm^(-2))为对照,探讨缩节胺施用量和施用时期处理对此种植方式下熟相的调节。结果表明:缩节胺用量180 g·hm^(-2)并于盛蕾期+初花期或盛蕾+初花期+盛花期使用后再通过脱叶催熟吐絮率均能达到90%以上,且吐絮强度高,较对照显著提高46.6%~71.4%。进一步回归分析表明,黄叶率保持在9.0%~12.8%之间,主茎红茎比为52.8%~53.1%,倒1果枝红茎比为28.3%~34.3%,倒2果枝红茎比为27.5%~39.8%,倒3果枝红茎比为34.3%~8.5%,倒4果枝红茎比为49.1%~51.5%,吐絮倒序位为7.1~8.1台最有利于集中吐絮。因此,缩节胺合理运筹能形成集中吐絮的熟相,为实现机采提供技术支撑。

不同短季棉品种生育进程中主茎叶内源激素的变化动态

以 3个生育和衰老特性不同的短季棉品种为材料 ,测定其在生育进程中主茎叶内源激素含量的动态变化。结果表明 ,短季棉的早熟性与主茎叶中早期吲哚乙酸 (IAA)和玉米素及其核苷 (Z +ZR)含量出现高峰值的时间一致 ,这 2种激素高峰值出现的时间愈早 ,其产量器官发育也早 ;短季棉的早衰性与主茎叶中后期脱落酸 (ABA)、乙烯和IAA出现的高峰时间一致 ,而与主茎叶中异戊烯基嘌呤及其核苷 (iP +iPA)含量相反。短季棉始絮后 ,主茎叶中iP +iPA含量低、ABA、IAA和乙烯含量高的品种易早衰 ,主茎叶中iP +iPA含量高、ABA、IAA和乙烯含量低的品种抗早衰。

棉花早熟性研究进展及其应用

早熟棉适于麦(油)后直播,实现粮棉一年两熟,对棉花产业稳定发展具有重要意义。本文对早熟性的遗传特性、早熟相关QTL定位、早熟相关基因挖掘的进展进行了阐述;总结了早熟棉的发展与育种现状以及早熟棉种质资源的创新利用;介绍了早熟棉在我国黄河流域、长江流域、西北内陆棉区的生产示范应用情况;提出了我国早熟棉育种的研究展望,为我国早熟棉育种提供参考。

基于SSR标记的陆地棉早熟相关种质遗传多样性分析

丰富的遗传变异对于提高作物的环境适应性和遗传改良进度至关重要。为了解我国早熟陆地棉种质资源遗传多样性,本研究利用136对SSR引物对186份陆地棉材料（96份早熟陆地棉材料和90份中、晚熟陆地棉材料）进行了遗传多样性分析,共检测到等位基因变异355个,平均2.61个。在早熟棉材料中,有134对多态性SSR引物扩增出341个条带,平均2.54个;中、晚熟材料中有133对多态性SSR引物,扩增出345个条带,平均2.59个。早熟棉材料的位点多态性信息含量（PIC）、有效等位基因数（Ne）、基因型多样性（H＇）分别为0.684、3.994和1.361;中、晚熟棉材料的PIC、Ne、H＇分别为0.668、3.852和1.343。早熟棉材料和中、晚熟棉材料的Jaccard相似性系数分别在0.349~0.935和0.270~0.907之间,平均为0.635、0.666。遗传相似性系数总体平均值接近,但早熟棉变化范围较中、晚熟棉小。用类平均法（UPGMA）进行聚类可将186份材料分成2个类群。总体上来看,供试材料遗传相似性系数较高,说明我国陆地棉早熟相关种质遗传基础狭窄。本研究结果为早熟棉育种亲本选配,早熟棉种质创新提供依据。

温光和种植制度对棉花早熟性和纤维品质的影响

研究了气候和种植制度对棉花早熟性和主要品质的影响,结果表明:棉花早熟性和纤维长细强指标受温光影响最大,熟制次之,栽培技术第三。进一步分析,气温中日最低温度对纤维品质影响最大。温光、熟制和栽培技术有互作效应,三者互作对细度影响最大,强度次之,长度影响最小;采用促早栽培,提高霜前花率有利于改进整体纤维品质。

北疆棉花“新陆早”系列品种主要性状分析

【目的】为北疆早熟棉种植选择及品种选育提供依据和参考。【方法】对"新陆早"系列41个品种的8个主要性状进行多元统计分析。【结果】皮棉产量与生育期极显著负相关,与铃重显著正相关,与衣分极显著正相关,与籽指、绒长、比强度、马克隆值无显著相关;通过回归分析和通径分析进一步表明,生育期、铃重、衣分与皮棉产量的直接通径系数依次为-0.226、0.203和0.501,回归方程为^Y=819.61-16.83X1+78.47X2+65.13X3;主成分分析显示5个主成分的特征向量累积贡献率达89.371%,依次为产量和品质选择综合因子、产量制约因子、籽指选择因子、生育期选择因子和品质选择因子。【结论】北疆早熟棉较好的协调了产量与品质之间的矛盾;生育期、铃重和衣分是影响产量的主要因素;增大衣分是提高皮棉产量的重要途径;新陆早13号、26号、36号、40号和42号品种综合表现优良。

早熟棉体细胞胚胎发生和植株再生体系的建立

以8个早熟或特早熟棉花为材料,通过不同激素组合(1.0 mg/L IBA+0.5 mg/L KT;0.1 mg/L 2,4-D+0.1 mg/L KT)诱导其愈伤组织,为早熟棉花的遗传转化以及基因功能研究奠定基础.结果表明,2种激素组合均能诱导产生4种主要类型的愈伤组织:淡黄色颗粒状愈伤组织,褐化的愈伤组织,翠绿致密的愈伤组织,疯长型愈伤组织.4种愈伤组织转入增殖培养基中前2种愈伤组织能够分化出胚性愈伤组织,胚性愈伤组织再转到分化培养基上培养能够产生胚状体,即体细胞胚;体细胞胚进一步发育成为再生小苗.用该组织培养再生系统,成功地使晋棉5号、中棉27号和辽棉10号等3个早熟棉品种在5～7个月内通过体细胞胚胎分化获得再生小苗.